Calculated initial vacancy ratios (<em>I</em><sub>L</sub> = <em>I</em>_{{ m KL}^{1}}:<em>I</em>_{{ m KL}^{0}}), extrapolated x-ray intensity relative to the main line (<em>R</em><sub>L</sub> = <em>X</em>_{{ m KL}^{1}}:<em>X</em>_{{ m KL}^{0}}) and to the total intensity (<em>R</em><sub>T</sub> = <em>X</em>_{{ m KL}^{1}}:<em>X</em>_{{ m KL}^{0}+{ m KL}^{1}}), average differences in <em>X</em>_{{ m KL}^{1}} intensity between oxides and pure elements extracted from the literature (ΔR<sub>L</sub>), and the product effect on the total x-ray yield C M Heirwegh I Pradler J L Campbell 10.6084/m9.figshare.1012792.v1 https://iop.figshare.com/articles/dataset/_Calculated_initial_vacancy_ratios_em_I_em_sub_L_sub_em_I_em_span_xmlns_xlink_http_www_w3_org_1999_x/1012792 <p><b>Table 1.</b> Calculated initial vacancy ratios (<em>I</em><sub>L</sub> = <em>I</em>_{{\rm KL}^{1}}:<em>I</em>_{{\rm KL}^{0}}), extrapolated x-ray intensity relative to the main line (<em>R</em><sub>L</sub> = <em>X</em>_{{\rm KL}^{1}}:<em>X</em>_{{\rm KL}^{0}}) and to the total intensity (<em>R</em><sub>T</sub> = <em>X</em>_{{\rm KL}^{1}}:<em>X</em>_{{\rm KL}^{0}+{\rm KL}^{1}}), average differences in <em>X</em>_{{\rm KL}^{1}} intensity between oxides and pure elements extracted from the literature (ΔR<sub>L</sub>), and the product effect on the total x-ray yield. Absolute uncertainties are listed in parentheses.</p> <p><strong>Abstract</strong></p> <p>Proton-induced x-ray emission (PIXE) was used to assess the accuracy of the National Institute of Standards and Technology XCOM and FFAST photo-ionization cross-section databases in the low energy region (1–2 keV) for light elements. Characteristic x-ray yields generated in thick samples of Mg, Al and Si in elemental and oxide form, were compared to fundamental parameters computations of the expected x-ray yields; the database for this computation included XCOM attenuation coefficients. The resultant PIXE instrumental efficiency constant was found to differ by 4–6% between each element and its oxide. This discrepancy was traced to use of the XCOM Hartree–Slater photo-electric cross-sections. Substitution of the FFAST Hartree–Slater cross-sections reduced the effect. This suggests that for 1–2 keV x-rays in light element absorbers, the FFAST predictions of the photo-electric cross-sections are more accurate than the XCOM values.</p> 2013-09-06 00:00:00 product effect oxide form vacancy ratios light element absorbers National Institute Technology XCOM kl FFAST predictions pixe Absolute uncertainties XCOM attenuation coefficients XCOM values intensity light elements rl parameters computations rt il Atomic Physics Molecular Physics